Hot top gasket



June 1, 1965 R. E. DALEY 3,186,Q42

HOT TOP GASKET Filed Dec. 26, 1962 INVENTOR. AaaERr E. DIALEY BY ATTORNEYS.

United States Patent 3,186,042 HOT TOP GASKET Robert E. Daley, 8355 Remington Drive, Pittsburgh, Pa. Filed Dec. 26, 1962, Ser. No. 247,109 1 Claim. (Cl. 277-11) This invention relates to the casting of metal into ingots, and more particularly to the sealing of the joint between the top of an ingot mold and a superimposed hot top.

It is desirable to use a superimposed hot top in making ingots, because a hot top resting on top of an ingot mold avoids forming a shoulder on the ingot in the upper part of the mold. Nevertheless, there has been an objection to the use of superimposed hot tops, due to the difiiculty in sealing the joint between the top of the mold and the bottom of such a hot top. Any leakage of metal at this point forms a projecting fin which adds to the cost of the ingot, because either the ingot must be treated further to eliminate the tfin, or in rolling the ingot the fin will be pressed down against the body of the ingot and require further conditioning of the product. Machined surfaces have been tried in order to provide an adequate seal, but they have not been very successful because of warpage of the comparatively light ledge at the bottom of the hot top casting. Asbestos rope and spun glass have been placed between the hot top and mold to form a seal, but the results have not been very good because of the difiiculty of handling and accurately positioning that material.

It is among the objects of this invention to provide between the bottom of a hot top and the top of an ingot mold a seal which is dependable, which is easy to handle, which is preformed to the desired shape, and which will always be correctly positioned.

In accordance with this invention a seal is formed between an ingot mold and a superimposed hot top by means of a gasket that includes a plastic ring which engages both hot top and mold. Completely or partly embedded in the plastic ring is a stiffening core, which holds the ring in substantially the same shape as the inside contour of the mold. The gasket is thus preformed to fit the mold. For best results, a portion of the gasket core projects down into the mold close to its inner surface to assure correct positioning of the gasket on the mold before the hot top is applied. The weight of the hot top compresses the plastic ring against the mold to form a good seal between them.

The invention is illustrated in the accompanying drawings, in which FIG. 1 is a fragmentary vertical section through the upper end of the mold supporting my gasket and hot top;

FIG. 2 is an enlarged plan view of the gasket alone;

FIG. 3 is a cross section of the gasket before the hot top has been set on top of it;

FIG. 4 is a view similar to the preceding figure, but with the hot top in place; and

FIG. 5 is a view, similar to FIG. 3, of a modified embodiment of the invention.

Referring to FIGS. 1 to 4 of'the invention, the hot top casing 1 may have any desired shape in horizontal section, but its central passage should conform to the shape of the inside of the ingot mold 2 that supports the hot top. The bottom of the casing is provided with'the usual integral inwardly projecting ledge 3. The inner surface of the casing preferably converges downwardly from the top of the casing to the bottom ledge, and the outside of the refractory lining 4 is tapered downwardly to the same degree. The inner surface of the lining converges up- 3,186,042 Patented June 1, 1965 wardly in the customary manner. The lining may be separated from the metal casing by a layer of separating material 5 that will burn out or deteriorate from the high temperatures encountered in use. To prevent the refractory lining from accidentally escaping from the casing before the hot top is used, the lining may be locked inside of the casing by suitable means, such as by an overlapping ring 6 removably connected to the top of the casing by threaded studs 7 or the like.

It is a feature of this invention that the hot top is spaced from the top of the mold by a sealing gasket of special form which seals the joint between the two. The sealing member itself is a plastic ring 10 that initially is preferably round in cross section as shown in FIG. 3, and that is made of a compressible plastic material which can Withstand the heat of molten metal. It preferably is made of clay mixed with oil, to which fillers such as asbestos, sand, vermiculite or graphite can be added. The plastic ring is preformed to the desired shape by a stiff core, usually of metal. The core shown is a plate-like ring 11 provided with perforations 12. It may be sheet metal with holes punched in it or it may be a wire screen. It is even possible to use heavy hard paper that has been treated to make it fire retardant. The core ring is partly embedded in the plastic ring by molding the plastic material against it with some of the material extending through some of the holes in the core so that the two rings are interlocked and can be handled as a single, more or less rigid, unit. 7

The core ring also holds the plastic ring in the shape of the core, which has been preformed to provide it with the same contour as the inside of the mold so that the plastic ring will rest on top of the mold a substantially uniform distance from the inner edge of the mold throughout the circumference of the ring. To make it easier to correctly position or center the gasket on the mold, it is preferred that a portion of the core project inwardly from the plastic ring and then extend downwardly a short distance into the mold close to its inner surface. This downwardly extending positioning portion may be a continuous lip or a series of circumferentially spaced legs or lugs 13.

After the gasket has been set on the mold as shown in FIG. 3, the hot top is lowered onto the gasket. The weight of the hot top will compress the plastic ring as shown in FIG. 4, so that it will form a good seal between the mold and hot top. Of course, when metal is poured into the mold it will consume the exposed portions of the core ring of the gasket, but that will not affect the plastic seal.

In the modification shown in FIG. 5, a plastic sealing ring 15 completely surrounds and conceals a stiff central core that is in the form of a heavy stiff wire 16. The wire is first formed with the same contour as the inside of the mold 17 with which the gasket is to be used, and then the plastic material is molded around the wire. To aid in positioning this gasket on the mold, a series of short wires 18 are spaced circumferentially around the gasket and each one is looped around the plastic ring. One end of each wire may be bent sharply to form a radial projection extending into the plastic ring to prevent the wire from rotating around the rings. The other end of the wire leaves the plastic ring and extends down into the mold close to its inner surface. This gasket is compressed in the same manner as the one first described herein when a hot top is placed on it.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claim, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

A hot top gasket adapted to support a hot top on an ingot mold, the gasket comprising a horizontal compressible plastic refractory ring that is substantially circular in vertical cross section, a central stiffening core completely embedded in the ring to hold it in a predetermined shape, and a plurality of circumferentially spaced wires wrapped around the ring, one end of each wire projecting from the ring downwardly adjacent the inner periphery of the ring substantially parallel to its axis, and the other end of each wire extending substantially radially into the plastic refractory to hold the wire against rotation 15 around the ring.

References Cited by the Examiner UNITED STATES PATENTS King 277-235 Lindemuth 22-147 Messler 22-147 Kinzel 277-11 Charman 22-147 Weisenburg 277-235 Nardin 277-11 Stinger 277-235 Kaufirnan 22-147 Wurtz et al 277-235 Yerrick 22-147 MARCUS U. LYONS, Primary Examiner. 

